# Endy0816

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## Posts posted by Endy0816

1. ### what is the difference between speed(units of c) and the Reciprocal in special relativity? Link below for reference

Going based off the table in the numerical values section; one is v/c and the other the multiplicative inverse or reciprocal of the lorentz factor.

v is always less than c, so for v/c you end up with: 0 ≤ β < 1

Now for the reciprocal of the lorentz factor you're doing the equivalent of finding the length of one side of a square with an area equal to the shaded section below.

Sqrt(1^2 - β^2)

2. ### Quarantine tunnel direct from the airport?

2 hours ago, ScienceNostalgia101 said:

Why not suspend travel until adequate facilities are built?

Money.

3. ### Are the regular expressions same?

1 hour ago, zak100 said:

(bba U aab)*= bba, aab, aab, bba ... or empty

Can't  we not have bbabbaabaab in the above regular expression?

(bba)* U (aab)* = bba, bbabba, bbabbabba, empty, aab, aabaab

Zulfi.

I want to say it should be:

(bba)* ∩ (aab)*

Just to be clear I'm assuming by 'U' you mean Union and by '*' negation.

4. ### A question about gravity and tidal energy

2 hours ago, Charles 3781 said:

Either way, the Moon's energy "expenditure" would seem to be the same. So the Moon  would keep orbiting the Earth at the same distance and speed.

The turbines on Earth, couldn't affect the Moon, could they?

Well, very slowly now mind you, the Moon is gradually moving away and the length of Earth's day increasing. If the Sun wasn't going to expand first, the Earth would end up being tidally locked to the Moon, with the Moon permanently in one spot of the world's sky.

Relative to the large amount of energy available and already being spent creating a traveling bulge, the impact of conventional tidal power will be pretty minuscule.

Should note that there are solar tides as well.

cross-posted

5. ### Do mitochondria really provide a lot of energy?

4 hours ago, molbol2000 said:

There is a contradiction here. If the mitochondria is energy efficient, then the aerobic regimen should provide maximum power. However, high-intensity exercise provided by an anaerobic regimen based on the Cori cycle

I think the problem is the availability of oxygen though they do make much more ATP.

Edit:

6. ### Screw downpipe

I've been reading where vortex breakers are used to improve roof drainage, but don't see any examples where a screw inside the pipe is used or know if a screw would work.

7. ### What do words mean?

13 hours ago, iNow said:

You need to ride an elevator to go get some crackers in the covered shopping area before you can reply? You must be hangry.

Very hangry. Although I'm being transported by a friend to buy small round cakes of leavened bread from a place where games can be played.

8. ### What do words mean?

I want to write a response but I need to go catch a lift to buy some biscuits at the arcade.

9. ### Bone loss in outer space and outer space ecology

13 hours ago, dimreepr said:

There's no such thing as fish, yet some of them have cartilage for bones...

I could definitely see that working for permanent low gravity downthe lone.  There's the reproduction aspect as well to consider too though. If we're forced to solve reproduction with artificial gravity or tricking our biology then bone loss may not even be a problem.

More research really needs to be done.  Honestly, for bone loss, might even be able to compensate enough via exercise where the risk upon landing after a longer trip is acceptable.

10. ### Bone loss in outer space and outer space ecology

On 10/5/2020 at 11:46 AM, tylers100 said:

From the article you posted:

Without causing side effects (as in zero)? I think it is impossible, really. Because of equilibrium or ratio principle; for a thing to be altered while it is in relation/relationship with existing other things, all of these must change in order to reach toward/back to an equilibrium. All of things as I said, include side effects. What I'm saying.. I think there will be always side-effects of some degree in principle in all drugs.

Maybe a next version of drug might will help human astronauts to go to ISS, the moon, to Mars, or elsewhere if we still have the notion; want a preservation of human body and its functions. If so, we have to consider the environmental design or ecological nature of spaceship and eventually to elsewhere - with earthy conditions in mind.

It is like carrying a baggage with a bit of everything in it. Too much manpower and costly.

The question is, once get there (eg. ISS, the moon, mars, etc) - how would the drug respond to a different condition over a long period of time? I mean, the drug and any future version(s) of it would be extensively tested here on Earth and orbit above.. positioned proximity to earth conditions, not the destinations as named above which have conditions that would be surely different from what is tested.

A solution for a situation, but that doesn't mean it is same for another or different situation. A saying. It is all situational dependent. And also, a drug is not always a solution, especially when faced with natural conditions (eg. outer space ecology, on Mars, etc) for a long time.

Anyway, have we yet to see if plants or mice undergo some kind of change over a long period of time in outer space without drugs, apart from the bone loss? I mean, plants or mice feed with natural food/drink/air and other basic and survival necessities. Just to see what happen. A long time, by that I mean, like.. over 1 year or so. To see the full impact of effects on it. Will it continue to be as it is, or until it encounter some kind of problems, or will it change to fit in a different ecological condition such as outer space?

Genetic tinkering would be more ideal in the long-term(more than just the bones that are impacted), but drugs should work well enough for early travel. Besides broken bones, you'll want to minimize risk of kidney stones and clogged toilets from the calcium. Probably wouldn't need to keep using it upon arriving somewhere either.

Environment there and on any colonies would be almost entirely artificial. The only real outliers are the lower gravity and higher radiation levels, though we could provide artificial gravity and radiation shielding if necessary.

Plants seem to handle low gravity fine. Humans have survived a couple years continuously living in space, but to my knowledge there haven't been any experiments lasting more than a few months for mice.

11. ### Q's about acceleration (Hijack from What fundamentally is acceleration?)

17 minutes ago, geordief said:

Doesn't the orbit decay?

Double checked myself. You're correct on orbital decay. I was only a considering the more conventional methods of a body losing velocity(drag, tidal forces), rather than gravitational radiation. Would thankfully still take forever and a day lol.

12. ### Q's about acceleration (Hijack from What fundamentally is acceleration?)

1 hour ago, geordief said:

I always thought that a system was in acceleration  because  it was expending energy and that its acceleration could be maintained only so long as the energy lasted.

The longer the acceleration was maintained the more the system dissipated and eventually it would vanish.

On the other hand a system that was in motion wrt another system could maintain that state for ever.

You can get a constantly changing Vector in circular motion too. Something in orbit can keep on going forever if left to its own devices.

13. ### What fundamentally is acceleration?

The accelerating twin is changing their position with respect to the rest of the universe, so the two won't be perfectly symmetric in that sense.

14. ### On the logistics (or lack thereof?) for road privatization...

2 hours ago, swansont said:

And you "forget" to bring your transponder with you while you drive, so the system thinks your car is still in the garage. Enforcement would be problematic.

It reminds me of the joke about how if the NSA tried to impose a tracking system on people in the USA there would be a revolt, but give them smartphones and they clamor for that system. So maybe it's a matter of making the transponder let you play candy crush...

But I think a database of where you go in your car that's active 24/7 would be a hard sell to some of the people, since there would be no confidence that the government couldn't obtain it.

I'm expecting it to be linked to the car even starting lol. Might still get violators but they're going to stick out like a sore thumb to enforcement agencies.

I don't expect this to really start up until various forms of car sharing become widespread.  I think when it is no longer a personal vehicle people won't mind so much and governments can realize the benefits.

15. ### On the logistics (or lack thereof?) for road privatization...

59 minutes ago, swansont said:

The scenarios we have in my neck of the woods are highway sections that are privately owned, and for which you pay a toll. Limited access, and there are slower publicly-available options.

There are also privately-owned roads in developments, sometimes as small as a single cul-de-sac, and sometimes with a small tree of roads within. Only residents and invited guests (including delivery vehicles) are expected to drive there. Sometimes enforces by a gate. It's not a through-road, though, even if there are multiple access points. Non-residents drive around. Money presumably comes from housing association fees, or something like that.

I doubt retail businesses would want to be located where people had to pay to drive to get to them, since it's an additional barrier to getting customers. It would take the parking meter situation and make it twice as bad.

If this were by street in a city, every car needs an E-Z pass-like transponder, compatible with all the monitors, and you need monitoring stations at every access point - which I imagine would be prohibitively expensive if there were multiple road barons. Much cheaper if it's at the entry and exit points, but now how do you collect for residents who never drive through an access point? You have to have a monthly fee in addition to tolls, if you have combination of residents and transients.

I was thinking a national system, where each car has a location tracker and valid account linked to it. Companies or communities could then charge based on actual usage, possibly factoring in income and other considerations.  Be simpler in most respects though would have some issues of its own naturally.

16. ### Bone loss in outer space and outer space ecology

6 hours ago, tylers100 said:

If my understanding of human bone is correct; The bone makes blood for body and in return, body needs the bone. When in outer space in a micro-gravity environment or no gravity at all, the relationship between body and Earth decreases to minimum or none at all thus minimum or presumably absence of a type of sustainability for bone.

The cause of bone loss is far more likely because of relationship between body and Earth (eg. gravity, etc), and of course with surface ecology in consideration.

Assumption 1 - Optimal Function: Then I think that body uses up what is available from bone (eg. blood). Bone will likely continue to provide until it is completely used up as long body require it. Once all used up, no manufacturing of blood then no renewable cells to sustain, repair, etc with the body thus human body will eventually either stop to function optimally until a possible death or something like that.

Or..

Assumption 2 - The Ecology of Outer Space: If a prolonged stay in outer space while supplied with survival requirements (eg. food, drink, etc) apart from gravity, would the human body undergo a change to fit in the ecology of outer space? If so, would that means we might have to redefine what it mean to be human being in outer space without gravity or other conditions (eg. Earth and its ecological surface) that give arise to conditional definitions of human beings?

Wiki explains it best:

Quote

Bone remodels in response to stress in order to maintain constant strain energy per bone mass throughout.[5] To do this, it grows more dense in areas experiencing high stress, while resorbing density in areas experiencing low stress. On Mars, where gravity is about one-third that of earth, the gravitational forces acting on astronauts' bodies would be much lower, causing bones to decrease in mass and density.[6]

Average bone loss of 1–2% was recorded in astronauts on Mir each month.[2] This is in comparison to 1–1.5% bone loss in the elderly per year, and 2–3% in postmenopausal women.[7]

Has been a new drug found that may help however,

Quote

The mice got a drug that prevented the usual decreases in muscle and bone mass during a month on the International Space Station, a team reports in the journal Proceedings of the National Academy of Sciences.

"The drug was effective not just in preserving the muscle mass and bone mass, but actually caused the muscles and bones to grow," says Dr. Se-Jin Lee, a professor at The Jackson Laboratory and the University of Connecticut.

Not sure how it would go if left unchecked. Bones also serve as a reserve of calcium for the body. Even if structural support and blood cells wasn't an issue, might still have problems.

17. ### On the logistics (or lack thereof?) for road privatization...

4 hours ago, swansont said:

The proffered scenario is one where this is not the case. Hence my "untenable" observation.

Ah see what you mean, was thinking only of the toll collection aspect. That part is at least technologically doable, though will probably have to wait until privacy concerns ease up with adoption of more transportation as a service options.

18. ### On the logistics (or lack thereof?) for road privatization...

1 hour ago, swansont said:

I don’t think the scenario you bring up is tenable.

Could possibly work with mass vehicle tracking. I imagine it working more as a tax based on miles driven though.

2 hours ago, ScienceNostalgia101 said:

Let's say, first street, second street, etc... intersecting with first avenue, second avenue, etc. Assume each of these roads are built by a separate company. Who then gets to run the intersections between these roads? Would it have to be a venture done jointly? If so, who gets to decide who gets the final say in some paving/streetlight placement/etc... decision in the context of these intersections? Would territory be demarked in an sealed-letter-like pattern? Even so, what rules would govern left turns, right, turns, etc...? And at the end of the day, what's stopping the company behind, let's say, first street, from colluding with the company behind, let's say, first avenue, to make their intersections with second street or second avenue harder to use?

Think if roads were all privately owned, a single company would likely have most or all of the contract for roads in a given area. That would eliminate most of the issues.

19. ### Interfering in other people's politics.

33 minutes ago, studiot said:

I didn't know the Falklands were either in the EU or near enough anybody els to have local discussions.

Why would they ?

Well Falklands were in EU via the UK and had been profiting considerably as a result.

Mercosur has been applying  political and economic pressure on them to try and secure the territory for Argentina.

20. ### Interfering in other people's politics.

5 hours ago, studiot said:

As has already been pointed out, the Swiss model has many points of attraction.

Even if British voters would accept paying into the EU budget, various rules and FoM, it looks like multiple EFTA countries would still veto the UK joining.

Kibd of curious, has there been any local discussion of plans regarding Gibraltar and Falklands?

21. ### Interfering in other people's politics.

14 hours ago, Royston said:

It's interesting how Brexit talks are influencing the Irish-American vote. All thanks to our 'special relationship'.

Pretty much yeah, easy way for Biden to show what sort of President he would be, while placing Trump in an awkward position.

Quote

As for chlorinated chicken, the House of Lords have recently blocked the move to import food that yields lower (than our current) animal welfare standards...

We'll have see what happens but is nice to see a measure of sanity returning to the UK.

22. ### Earth to Venus

1 hour ago, dimreepr said:

It may also argue for the only viable answer to life.

Yes, that is a distinct possibility as well.

23. ### New dimensioning garbage...

Those are dash sizes.

I think you want a -2 or 2/16.

edit: Which I don't see on that page...

...and no idea but I know your pain. Ordering parts sucks for hoses and pipes.

24. ### Interfering in other people's politics.

I swear sometimes forget that all this is real. Took way too long to figure out why Bloomberg would be interviewing the Irish Ambassador on EU-US relations. 😐

25. ### Earth to Venus

If genetics were similar that might argue for a common origin.

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